相变与微裂纹对HMX晶体高温下撞击感度的影响机制

为了研究高温下炸药撞击安全性中存在的多因素耦合问题,设计了高温炸药撞击感度试验装置,并建立了高温炸药撞击感度试验方法。结合扫描电镜和X射线衍射技术,采用所建立的试验方法,研究了奥克托今(HMX)晶体颗粒高温撞击过程下的响应。结果表明,随着温度升高,HMX晶体颗粒的落锤撞击感度逐渐升高。同时,HMX晶体品质随着温度升高逐渐变差,140℃时有少部分晶体碎裂,180℃时较多的晶体碎裂,当达到200℃时,HMX晶体全部碎裂;HMX的β→δ相变发生在184～186℃。降至常温后δ相晶体逐渐恢复为β相,撞击过程有助于β相的恢复。影响热加载前后HMX晶体颗粒撞击感度的主导因素包括温升、微裂纹和相变,不同影响因素起作用的温度段是不同的。     

HMX基混合炸药烤燃特性及多步热反应计算

对以HMX为基的HMX/粘结剂/95/5混合炸药进行了多点测温的烤燃实验,获得了炸药内部不同位置的温度变化历程,观测到了炸药加热过程中由于HMX从β相到δ相的晶型转变吸收热量引起的温度非线性变化。通过不同尺寸炸药烤燃弹实验,研究了装药尺寸对炸药烤燃过程的影响。结果显示,在相同加热条件下,不同尺寸炸药内部温度分布不同,炸药内部相变情况、点火时间和区域有差异。HMX/粘结剂/95/5炸药烤燃点火后会发生强烈爆炸。建立了HMX/粘结剂/95/5炸药热反应计算模型,考虑了HMX多步热分解反应。采用过渡态理论,描述HMX炸药固相相变。根据炸药多点测温烤燃实验的结果,标定了HMX/粘结剂/95/5炸药热反应动力学参数。计算出了HMX晶型转变吸热引起的温度变化。通过对不同尺寸的烤燃弹实验的数值模拟,验证了计算的准确性,实现了对不同条件下炸药烤燃过程的有效预测性计算。计算获得了不同时刻下HMX热反应过程中反应物、中间产物和产物质量浓度的变化情况。     

HMX晶体颗粒微结构的原位变温X射线小角散射

为了研究温度作用下奥克托今(HMX)晶体的微结构演化和热安定性,使用原位变温X射线小角散射(SAXS)和广角散射(WAXS),对比研究了平均粒径为5μm和20μm两种HMX晶体颗粒的缺陷演化和相变行为。WAXS结果表明,HMX(5μm)的β→δ相变起始温度为194℃,比HMX(20μm)的相变起始温度高8℃。Guinier定理拟合分析表明,两种HMX晶体在150℃均开始生成微缺陷,其回转半径约为0.9 nm;随温度升高,微缺陷的体积分数增加,高温下生成的微缺陷在降温过程不会消失;HMX(20μm)的微缺陷含量高于HMX(5μm)。微缺陷的累积会导致HMX晶体内部生成微裂纹,甚至发生开裂。SAXS、WAXS和扫描电镜观测结果均表明HMX(5μm)具有更为优异的热安定性。讨论了微缺陷的生成机制,以及微缺陷对HMX感度的潜在影响。     

高聚物黏结剂对HMX相变行为的影响

为了探究高聚物黏结剂对奥克托今(HMX)相变行为的影响,使用压装成型工艺制备了含聚酯型聚氨酯(HMX-Estane)、氟橡胶(HMX-F₂₃₁₄)、硝化纤维素(HMX-F₂₃₁₄-NC)的HMX基高聚物黏结炸药以及纯HMX药柱,利用原位变温X射线广角散射(WAXS)技术和差示扫描量热法,研究了热刺激下样品中HMX的相变行为和机制。WAXS结果表明,HMX-Estane(95∶5)、HMX药柱、HMX-F₂₃₁₄(95∶5)、HMX-F₂₃₁₄-NC(95∶3∶2)的相变起始温度(Ti)分别为186℃、188℃、192℃、198℃。相比于HMX药柱,黏结剂中加入少量的NC(2%),Ti可提升10℃。真空条件下,4种样品从高温δ相降温至100℃保温,只有HMX-Estane发生了δ→β逆相变且在3.5 h内δ相全部转变为β相,而其他样品均未发生相变,仍为δ相。β-HMX在HMX-Estane界面位置的溶解(升温过程)和析出(降温过程)可能是促进HMX-Estane发生β→δ相变,及其逆相变的主要因素。     

慢烤过程中热应力对HMX基含铝炸药装药响应特性的影响

为获得炸药装药在慢烤过程中热应力的变化规律,设计了一套热应力测试装置,获得了奥克托今(HMX)基含铝炸药装药在密闭约束条件下热应力随温度的变化曲线;通过调整烤燃弹内惰性包覆层与装药的体积比,改变慢烤过程中装药热应力的上升速率,研究了烤燃弹临界响应温度及其三种工况下的响应剧烈程度。结果表明,壳体的约束作用使得装药的热应力随着温度的上升而逐渐增大,根据热应力变化速率的差异,可将整个过程分为6个阶段,其影响因素依次为热膨胀、孔隙率下降、HMX晶型转变、HMX缓慢分解、部分小分子气体泄漏、HMX加速分解,当温度升至208℃时,热应力达到9.2 MPa,装药随即点火;在烤燃弹的装药表面增加热膨胀性较强的硅橡胶包覆层,则会加快装药热应力的增长速率,使得装药的临界点火温度下降,但不会改变装药响应的剧烈程度。     

HMX的β→δ晶型转变研究进展

奥克托今（HMX）是最重要的含能材料之一,广泛应用于各种推进剂和炸药。HMX发生爆轰前将发生β→δ晶型转变,研究HMX的β→δ晶型转变规律可以加深对HMX的感度、爆轰过程和贮存安全性的认识。本文从HMX的晶体结构、晶型转变动力学和晶型转变影响因素三个方面对HMX的β→δ晶型转变进行了综述,并提出以HMX的晶体品质及固体添加剂对β→δ晶型转变的影响作为今后的研究方向。     

含孔洞缺陷的δ-HMX晶体的分子动力学模拟（英文）

采用分子动力学(MD)方法,模拟了δ-HMX晶体中的孔洞缺陷演化和分子构象变换,并与β相对比。模拟体系包含一个大小为30个HMX分子的孔洞缺陷,对应10%的空位浓度。采用QST3法计算了分子构象在真空中的转换能垒,结果表明,所有的构象转换均具有较低的活化能。当模拟温度为500 K时,不管是δ相还是β相,整个晶体均塌陷成液态,并伴随大的晶格膨胀。在塌陷的液态分子中,可观察到四种分子构象α,β,BB和BC,同时与这四种分子构象共存的还有大量的过渡态或中间体结构。在MD模拟过程中,跟踪单个分子随时间的演化,能发现分子在不同构象间频繁转变,这是较低的转换能垒所致。当模拟温度降低到300 K和200 K时,两个晶相(β和δ)表现出不同的演化趋势。对δ-HMX体系,在发生孔洞塌陷的同时,整个晶格也失去了严格的周期结构,但是嵌在β-HMX晶格中的孔洞却被保留下来,仅发生了孔洞的收缩和少量分子向孔洞中心的迁移。此外,与δ-HMX的晶格收缩相反,β-HMX的晶格随模拟温度升高持续膨胀。     

含孔洞缺陷的δ-HMX晶体的分子动力学模拟（英）

采用分子动力学(MD)方法,模拟了δ-HMX晶体中的孔洞缺陷演化和分子构象变换,并与β相对比。模拟体系包含一个大小为30个HMX分子的孔洞缺陷,对应10%的空位浓度。采用QST3法计算了分子构象在真空中的转换能垒,结果表明,所有的构象转换均具有较低的活化能。当模拟温度为500 K时,不管是δ相还是β相,整个晶体均塌陷成液态,并伴随大的晶格膨胀。在塌陷的液态分子中,可观察到四种分子构象α, β, BB和BC,同时与这四种分子构象共存的还有大量的过渡态或中间体结构。在MD模拟过程中,跟踪单个分子随时间的演化,能发现分子在不同构象间频繁转变,这是较低的转换能垒所致。当模拟温度降低到300 K和200 K时,两个晶相(β和δ)表现出不同的演化趋势。对δ-HMX体系,在发生孔洞塌陷的同时,整个晶格也失去了严格的周期结构,但是嵌在β-HMX晶格中的孔洞却被保留下来,仅发生了孔洞的收缩和少量分子向孔洞中心的迁移。此外,与δ-HMX的晶格收缩相反,β-HMX的晶格随模拟温度升高持续膨胀。     

装甲钢温度-组织-应力耦合本构模型的建立及在焊接模拟中的应用

装甲钢焊接热循环过程中固态相变对焊接残余应力的演变及大小有着重要影响,而现有的有限元软件本构模型无法考虑固态相变的作用。在传热学、固态相变理论和连续介质力学的基础上,建立了温度－组织－应力耦合的本构模型,本构模型中综合考虑了固态相变引起的体积变化、力学性能变化和相变塑性对焊接残余应力的影响,采用ABAQUS子程序UMAT通过二次开发将该本构模型嵌入通用有限元软件中,对装甲钢平板对接焊进行研究,获得了装甲钢焊接热循环过程中温度、组织及残余应力变化规律。研究结果表明：装甲钢平板中断面表面宽度方向,在纵向残余应力表征上,耦合本构模型的模拟结果与X射线衍射测量结果具有较好的一致性,验证了耦合本构模型的正确性,并表明相变塑性对相变区的残余应力存在一定的松弛作用;对于装甲钢近缝区纵向残余应力大小：完全相变区＜部分相变区＜未发生相变区。     

360 nm紫外激光辐照下HMX晶体的微观结构变化

为了研究奥克托今(HMX)晶体的激光辐照效应,采用多种技术手段表征了HMX晶体在360 nm紫外激光下的微观结构演化.光学显微镜下观察了激光辐照下HMX晶体内部的缺陷积累直至细化开裂的过程.通过对原位拉曼光谱分析发现HMX吸收紫外光子后会激发HMX分子,引起环的振动.采用原位广角X射线散射(WAXS)、单晶衍射(SCXRD)和原位小角X射线散射(SAXS)技术研究了HMX在紫外激光辐照过程中的晶体变化及缺陷演化,发现HMX不会发生相变但会细化并产生新的缺陷.原位SAXS结果表明,激光辐照1170 min后HMX孔隙不断增多,并在10～20 nm和30～40 nm两个区域呈双峰分布.激光辐照过程中HMX的小尺寸孔隙不断增多并逐渐融合成更大尺寸的孔隙,缺陷不断累积,微孔隙延伸成微裂纹,再扩展成宏观裂纹.     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.     

A Study on the Estimation of Aeroheating upon the Warhead Nose at Supersonic Speed

An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD （computational fluid dynamics） and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.